Method and means for controlling the operation of vehicle propulsion units



ING'-"I'HE OPERATION OF VEHICLE PROPULSION uun's 3 Sheets-Shoot 1 April 13 1926.

JJA. MCGREW El" AL METHOD AND mums FOR CONTROLL Filed Dec A rii 13,1926.

J. A. MQGREW ET AL METHOD AND MEANS FORACONTROLLING mmopsm'rxou OF VEHICLE PROPULSION UNITS Filed Dec. 15 1921 &

3 Sheets-Shoot 2 awuantom Ja/zzz AMI/( rew Jamw'ffioree Patented Apr. 13, 1926.

UNITED STATES PATENT'OFFICE.

JOHN A. MGGREW AND JAMES T. LOREE. 0F ALBANY, YORK.

METHOD AND MEANS FOR CONTROLLING THE OPERATION OF VEHICLE PROPULSION UNITS.

Application filed December 15, 1921. Serial No. 522,525.

T 0 nil whom it 'nm-g concern: I

Be it known that we, JOHN A. MoGnnw and JAMES T. Loam-2, both citizens of the United States, and residents of the city of Albany, county of Albany, and State of New York, have invented certain new and useful Improvements in Methods and Means for Controlling the Operation 'of Vehicle Propulsion Units, of which the following is a specification.

This invention relates to an improved method and-means for controlling the operation of vehicle propulsion units.

One of the important problems which remains to be solved in connection with railway conditions, notwithstanding the great inventive activity in this art in recent years, is to secure sufficient power in locomotives of the present standard construction Which,- in addition to the propulsion of a train at the desired operating speeds over the main line will also quickly move heavy trains from terminals and over road gradients.

we may mention the now well'known Mallet type of locomotive. This locomotiveis equipped with a compound engine which may be converted for operation as a simple locomotive at lower speed. It has been found, however, thatsuch operation is limited to speeds not exceeding about eight miles per hour, and it is impossible to provide the engine with cylinders of proper diameters so that it may operate both as acoinpound and simple engine without quickly ovei'taxing the capacity of the boiler. Also, in the operation of a Mallet locomotive as a simple engine there is considerable racking or straining of the mechanism so thatthe engine shop.

Our present invention does 'not contemplate any new locomotive construction or radical departure from existing, types but is to be identified with that particular branch I of he art which relates to what are known. as booster, supplementary or auxiliary motors for locomotives, the purpose of which is to increase the tractive power at low or moderate speeds. lVe are aware of the fact that it has heretofore been proposed to operate such a booster motor from -the motor is frequently in the repair further moved to operate the valve and power supply carried by the locomotives for the primary propulsion unit. In the contemplated arrangement the cylinders of the booster motor were connected by a supply pipe to the steam dome of the locomotive boiler and a throttle valve was interposed in said piping and controlled by a compressed air actuated valve, the air supply in turn being controlled by mechanism actuated by the reverse lever of the locomotive. Additional valve means actuated when the main throttle was opened to supply steam to the main engine cylinders finally released the air forthe operation of the throttle valve first referred to so that steam from the dome was supplied to the booster engine. Among the numerous objections to such an apparatus .was the fact that the booster motor was only operative when the reverse lever controlling the valve gear was in its full forward or reverse positionso that the maxi-' were necessary together with a relatively complicated mechanism for opening the valve for the booster motor, more or less uncertain in its operation and comparatively difficult for the mechanic to understand in its construction and operation. The booster motor in this case was thrown into gear or entrained with the axle driven thereby by means of compressed air while the drivinggear of the motor was stationary or inactive. Mutilation or stripping of the gear teeth was, therefore, unavoidable. Again, it was proposed to employ a pedal operated means to check the throw of the reverse lever to its full forward .or rear po sitions, the actuation of such means being required before the reverse lever could be With the foregoing brief review of prior developments in the aft, the radical departures whichwe have made and the simple and effective character of the present disclosure, will be more readily appreciated. Not only do we propose to avoid a highly complicated apparatus-with its attendant uncertainties in: operation to which we last referred, but we also have evolved a distinctly new method and means for the operation of such booster or auxiliary motors with which standard types of locomotives may be equipped without necessitating any radlcal changes in structure.

In accomplishing our purpose we propose a method and apparatus whereby the operation of one or more booster or auxiliary motors may be automatically synchronized with the operation of the primary propulsion unit and rendered simultaneously effective therewith by the utilization of the pressure influence of the steam supplied from the locomotive. Not only do we aim to secure'such synchronization in the operation of the main and auxiliary propulsion I of the present invention is to provide a single throttle method of control for the operation of the primary unit together witlrthe auxiliary or booster motor and which will, therefore, be entirely independent of the manipulation of the reverse lever, thus making possible the operation of the booster at maxi mum power output when the primary unit is being operated at less than full cut-off. It is of course well known b locomotive engineers that at low and mo erate speeds there is considerable surplus potential horsepower. This surplus otential steam ener y supply of the locomotive boiler is effectivedy crease t and is converted into useful energy utilized merely by opening the usual throttle valve with which the locomotive is eqlgippled he or booster motor to materiall y e effective tractive-power. It is another object of our present 1mauxiliary provements to utilize superheated steam for I tion of the steam in the'cylinders of said the operation of the auxiliary propulsion unit, thus reducing to a minimum condensaunit. In so far as we are aware, in all prior efforts towards a-successful solution of this roblem, the steam for the operation of the ooster motor was taken from the boiler by connections so located that only saturated steam was available. One-of the principal reasons for failure in the practical operation of these prior art deviceswas due to excessive condensatlon of the saturated steam .at a high degree of superheat, the steam pipe connection being made at any place between the main engine cylinders and the iliary or booster propulsion unit and also superheater header. In fact, if. desired, the connection might be made to the superheated steam chamber of the header itself.

It is another important object of our invention to provide means actuated by the steam pressure in its passage tothe cylin ders of the auxiliary propulsion unit to govern the initial operation of said propulsion unit and also actuate the means where'- by said unit is operatively entrained with or connected to the axle to be driven thereby As will be hereinafter more clearly dis- 0 osed, 'we entirely discard the systems of air pressure control for the entrainment gearing as heretofore employed and effect .such action as well as a governed control of the initial operation of the propuslion unit by means of the power of the steam itself which, immediately after full entrainment of the auxiliary motor with the axle, actuates said motor at maximum power. This feature of our invention entirely obviates the possibility of stripping or mutilating the teeth of the entrainment gears or placing the parts of the booster motor under excessive strains.

In addition, it is an object of our invention to provide means for controlling the passage of the superheated-steam to the cylinders of the booster motor wherebythe entrainment gearing may be actuated to reverse the direc tion of rotation of the driven axle when the valve gearing of the main engine cylinders is reversed.

Owing to the simplicity of our present improvements, our invention is well adapted for application and use in connection with .'a multiple arrangement of the booster or auxiliary motors which are controlled and rendered simultaneously effective as an aid to the main engine cylinders by the mere manipulation of the ordinary single throttle. With the above and other objects in view, the invention consists in the improved method of operation and control of the auxin the several novel features of the apparatus employed, as will be hereinafter more fully described, illustrated in the accompanying drawings and subsequently incorporated in the subjoined claims.

In the drawings wherein we have disclosed an adaptation of our present improvements which have given highly satisfactory results in service and in which similar reference characters designate corresponding parts throughout the several views:

Figures 1 and 1 illustrate a locomotive and its tender of conventional type, showing the same equipped with our present improvements;

Figure 2 is a diagrammatic view illustrating a multiple arrangement of the auxiliary propulsion units;

type of locomotive and tender. The locomotive includes the usual boiler 55 having a steam generating capacity requisite for the development of maximum horse-power from the engine as determined by the bore of the en ine cylinders 6.. The usual steam 'distri liuting chest 7 is provided for the engine cylinders in which the sliding cut-oil" valve is housed. As is well known, the cutofl? valve is'actuated bya valve gear, such for instance asthe Walschcrt gear, wh ch 1n turn is operativcly connected to a suitable power reverse mechanism, which for example, might be of the Ragonnet or other well'known type. Owing to the familiarity of those skilled in the. art with this valve gear and reverse mechanism, it is not necessary to further refer to the same in detail.

It will suffice to state that the latter is- The locomotive is further provided with a steam superheater indicated at9. This superheater likewise may be of any desired type and includes a superheater header to which the various superheater units extending into the fire tubes of the boiler are con nected. The pipe 10 is connected, to the saturated steam receiving chamber of the superheater header at one of its ends, the other end of said pipe being provided with the usual throttle valve 11 located in the steam dome 12 of the boiler 5. Pipes 13 lead in opposite directions from the superheated steam chamber of the superheater header through opposite sides of the smoke box and are connected to the steam chests 7,.- The throttle valve 11 is actuated by means of the throttle valve lever 14 also located in the engineers cab.

The tender 15 which is coupled to the locomotive may be of any conventional con struction. Oneof the supporting trucks for the tender carries the auxiliary propulsion cludes cylinders 17 in which pistons reciprocate, said pistons being connected to crossheads 18. These cross-heads are operatively connected to a drive shaft l.) from which power is transmitted by gearing to be pres ently described in detail, to the driven axle 20. For a more detailed understanding 0! this auxiliary propulsion unit, reference may be had to the patent above referred to. Steam is'supplied to the booster motors through the insulated pipe or conduit 21 which may be made up of sections suitably mounted upon one side of the locomotive and beneath thebody of the tender, said sections being flexibly connected in any suitable way between the locomotive; and tender. One

end of the pipe 21 is coupled to the outlet side of a valve casing 22 and to the inlet side of the valve casing pipes 23 leading from the superheated steam supply pipes for the steam chests 7 are coupled. For conveniencein the application of the apparatus-we have shown these pipes 23 connected to the feed pipes 13'exteriorly of the locomotive smoke box. However, it desired, such connection may be made to the pipes 13 within the smoke box or, indeed, directly to the superheated steam chamber of the'superheater header 9. .lVithin the valve casing-22 an air pressure actuated valve 24 of any conventional form is arranged and normally outlet sides of the valve.

The other end of the conducting pipe 21 is connected to a by-pass valve 25,-the movable valve element 26 of which. is likewise actuated by compressed air. A pipe 27 is connected to the by-pass valve casing at one side of the valve 26 and is'normally in open -communication with the pipe 21 as seen in Figure 4. At its other end this pipe 27v is coupled to one end of a cylinder 28 havmg an angular outlet branch 29 which is connected to the feed pipe 30 leading to the'cylinders 17 of the auxiliary propulsion unit. 7

A piston 31 reciprocates in the cylinder 28 and .]S normally urged in one direction by a suitable spring to the position seen in Fig ure 4, where it closes communication between the outlet nipple 29 of said cylinder and the pipe 27. This piston is operatively closes communication between the inlet and connected to a frame 32 fulcrumed upon the driving shaft19 of the propulsion unit and having a gear 33 mounted therein which is constantly in mesh with the gear 34 fixed upon said driving shaft.

On the driven axle 20 a gear 35 is fixed. Upon the admission of superheated steam to, the pipe 27, said steam acts against the piston 31. In the movement of this piston motion is transmitted to the framev32 carrying gear 33 and said gear is moved towards the gear 35. However, before these gear elements can come into mesh with each other,

I the port leading to the outlet 29 is uncovered by the piston so that steam enters through pipe 30 into the cylinders of the auxiliary propulsion unit. The operation of said prouilsion unit is thus started so that while the teeth of the gear 33 are substantially in peripheral contact with the teeth of the gear 35, rotation is transmitted to the gear 33. Instantaneously, upon the registration of the teeth of gear 33 with the spaces between the teeth of gear 35, the steam pressure behind the piston 31 acts against said piston to further oscillate frame 32 and thus bring about the complete entrainment of the gears. The full volume of steam then passes through pipe 30 into the cylinders of the propulsion unit which is operated at its maximum speed.

At the opposite side of the valve element 26 the by-pass valve is connected to a second cylinder 36 in which a piston valve 37, similar to the piston 31, operates, normally closing communication between the outlet nipple 38 and the by-pass valve chamber. This nipple is connected by pipe 39 to the cylinders 17 of the propulsion unit. The piston 37 is operatively connected by suitable links 40 to a reversing gear 41 which is in constant mesh with the driven gear 35 but is circumferentially movable therearound so that it may be shifted under the action of the steam pressure against the piston 37 into meshing engagement with the gear 33 driven by the propulsion unit and thus reverse the direction of rotation of the axle 20.

The by-pass valve 25 above referred to may be of any 'desired construction. The piston valve means controlling the entrainment of the booster motor with the driven axle constitutes the subject matter of a separate application for patent and accordingly, is not claimed herein. Likewise the combinations comprising the means for entraining the driving gear of the auxiliary propulsion unit with the axle for the forward and reverse drives are specifically described and claimed in additional co-pending applications.

The supply of superheated steam to the cylinders of the auxiliary propulsion unit is controlled through the medium of an air valve 42 suitably mounted in the engineers cab. This valve may-be of any approved construction and receives compressed air through the pipe 43 from a supply tank 44 carried by the locomotive. If desired, however, this pipe might be connected to the brake control train pipe system as only a relatively small quantity of air is required for the purposes of our invention. For purposes of illustration we have illustrated the valve 42 as being provided with two independently operable valve members 45 which normally close communication between the air receiving valve chamber and the pipes 46 and 47 which are connected thereto. These pipes respectively, supply air under pressure to the valve 22 and to the bypass valve 25. To the valves 45 the pivoted levers 48 and 49 are respectively connected. The control lever 50 actuates the cam elements 51 and 52 which cooperate with the respective levers 48 and 49 to open the valves 45. As shown, when the lever 50 is in the neutral position A both of the valves 45 are closed. Upon the movement of said lever to the position B the cam 51 actuates lever 48 and lifts one of the valves 45 from its seat, the other valve remaining closed. Thus, compressed air is supplied to the valve and the valve member 24 moved to its open position. Accordingly, when the throttle 11 is opened by the engineer, the superheated steam in its passage to the cylinder chests enters pipes 23, passing through the valve 22 and into the conducting. pipe 21. The element 26 of the by-pass valve being in its normal position, the superheated steam passes through pipe 27 and acts against the valve piston 31 to effect the entrainment of the gearing of the auxiliary propulsion unit with the gear on the driven axle in the man ner above explained. In this operation the axle 20 is driven to aid in the forward propulsion of the train.

Upon the reverse movement of the control lever 50 to position C the cam element 51 again acts upon lever 48 while the cam element 52 coacts with lever 49, thereby opening both of the valves 45. Compressed air will now be supplied not only to the valve 22 but also through pipe 47 to the casing of the by-pass valve 25 and move said valve into position to cut of]? communication between the conducting pipe 21 and the pipe 27 and open communication between said pipe 21 and the cylinder 36 so that there- 'versing gear 41 will be actuated and moved into effective engagement with the transmission gear 33 of the propulsion unit. The direction of rotation of axle 20 will thereby be reversed to increase the tractiv'e power in the backward propulsion of the train. The cam 51 is of such form that the by-pass valve 26 is actuated as just explained slightly in advance of the opening of the valve 22 so that connection between the pipes 21 and 27 will be completely out 011 before the reverse gear is actuated.

From the foregoing it will be seen that our new method of control for the auxiliary or booster motor consists in the utilization of the surplus superheated steam from the locomotive boiler when traveling at low speeds for the purpose of automatically controlling the entrainmentof the motor gearing with the driven axle and starting the maximum horsepower output.

' gearing and position the cutaofl" valve. As is I driven thereby. Therefore, it is possible with our new method of control to relieve or .hook up the reverse lever and thus reduce the horse-power output. of the main engine cylinders while the operation'of the auxiliary propulsion unit is continued at its We are, therefore, enabled to operate a locomotive equipped with our present improvements with a more economical consumption of power under varying road and load conditions than is possible in the use of apparatus such as has heretofore been proposed for the accomplishment of the same purpose.

Assuming that the locomotive is to be driven in a forwardidirection, the reverse lever 8 is first actuated to operate the valve well known, for any given percentage ofcut'- oil in the main engine cylinder there is a corresponding horse-power outputfor a given I boiler pressure. Thus, if the reverse lever is moved to the limit of its forward posit on,

superheated steam enters the engine cylinders throughout 'substantially the entire stroke of the piston and the highest horseower output, and consequently the greatest ractive power, is obtained. '.When the dr ving speed is increased the cut-oil of the cylinder is shortened so that the istons are operated partly by expansion 0 the steam, the degree'of cut-off depending upon the driving speed which it is desired to maintain. After properly positioning the reverse lever, the lever is moved to the position B, thus opening the valve 22 as'above explained so that superheated steam .is sup: plied from pipes 13 through pipes 21 and .27 to the entraining vvmechanism for the forward drive. gears of the auxiliary propulsion unit. In the initial movement of the piston valve 31 under" steam pressure, the

' transmission gear is moved around the drive -.and

trainment of the gears is gear 34; until said valve is in position to partly open communication between pipe 27 the outlet 29 leading to the cylinders 17. The propulsion or booster motor s thus first; operated at low speed and thetrans- --mission gear 33 is rotated until its teeth are in position to properlymesh with the teeth of the gear 35. The instantaneous full enthen effected by the continued movement of the piston valve 31 which completely uncovers the outlet 29,

full speed takes place. It is thus apparent that the operation of the auxiliary propulsion unit is entirely controlled (after the' lever 50 has been properl set) by the single throttle valve with whic the locomotive is equipped to control the supplyv of steam to the main engine cylinders; The reverse lever may be retrieved or hooked up to shorten the cut-off to any desired extent without in any way affecting the operation of the auxiliary propulsion unit. In other words, after the setting of the air valve lever 50, the apparatus requires no further attention from the engineer but is automatically controlled merely by'the opening and closing of the usual'throttle valve 11.

Upon a movement of the lever 50 to the position C, the superheated steam is supplied throughthe by-pass valve 25 for the operation' of the piston valve 37 thereby entraining the reverse gear 41 with the gear 33 in the same manner as'the latter gear was entrained with the gear 35 for the forward drive as above explained.

A-further advantage incident to our iniproved' method of control is that when the throttle is closed to permit the locomotive to coast on a down grade, the auxiliary propulsion unit is instantaneously disentrained 'from the driven axle without necessitating any change inthe position'of the lever .50.

Upon reaching the bottom of the grade, the

engineer again opens the throttle and the auxiliary propulsion unit is automatically rendered effective simultaneously with .the voperation of the main engine without requiring the actuation of other control valves by the engineer. It .Will thus be Seen that we.

have provided a system or method of single throttle control for auxiliary propulsion units or booster motors which may be prac tically carried out by means of an exceedingly simple apparatus requiring no especial skill or expert knowledge upon the part of the engineer in its operation. The use of superheated steam for the operation of the auxiliary propulsion unit is a very important consideration as actual demonstrative tests have shown that condensation in the cylinders of the propulsion unit is reduced to a minimum. Such tests have also shown an increase in tractive power of approximately 35%. In order to secure such a power 1ncrease by changes in locomotive design, a

very considerable increasein the size and weight of the locomotive would be necessary in order to obtain the requisite boiler steam pressure. Such locomotives would not only be exceedingly expensive, but they would also be of such great weight that the reconstruction or at least the material strengthening of existing bridge structures would be required, thus further adding to maintenancecost. Our present improvements on the other hand, can be applied at comparatively small cost to existing standard types of locomotives without necessitating structural changes therein of a radical character.

As we have illustrated in Figure 2 of the drawing, it is possible to arrange the auxiliary propulsion units in multiple for increasing the tractive power of large size locomotives hauling heavy loads. Thus the pilot or trailer truck of the locomotive or both of such trucks as well as the tender trucks, may be provided with booster motors orpropulsion units. In such multiple operation of the propulsion units, said units are simultaneously controlled and rendered effective or ineffective in the operation of the throttle valve, it being necessary to provide only'a single valve 22 and a single by-pass valve 25, said latter valve being connected with the series of propulsion units by suitable piping in a manner which will be readily understood. Thus in this case likewise, the plurality of auxiliary propulsion units are controlled and operated by a single throttle synchronously with the main locomotive engine However, we have found that for use in connection with small size locomotives such as are generally used for hauling freight trains, a single booster motor or propulsion unit will suffice.

From the foregoing description considered in connection with the accompanying drawings, the nature of our present invention and the manner of its operation in practice will be readily understood. By reason of the single throttle control whereby the booster. motor is rendered effective independently of the reverse lever or other control parts of the locomotive, we have succeeded in greatly simplifying the necessary apparatus,

1 and thereby proportionately reducing the expense incident to equipping the locomotive v with auxiliary propulsion means of this character. By way of example we have herein disclosed an embodiment of the apparatus which has been subjected to very severe tests in actual practice and has produced highly satisfactory results. Nevertheless, it will be understood that we do not deem ourselves necessarily limited to the particular apparatus disclosed as our improved system or method of control might be exemplified in various other forms of such apparatus and in the relative arrangement and construction of its several parts. Accordingly, we reserve the privilege of resorting to all such legitimate modifications as may be fairly embodied within the spirit and scope of the invention as claimed.

V7 e claim:

1. The method of aiding a locomotive engine in the propulsion of a train, which consists in utilizing the steam supply of the main engine of the locomotive for operating an auxiliary propulsion unit, and in controlling the supply of steam to said unit throu h the medium of means directly actnated by the pressure influence of the steam and operating to establish a driving connection between said unit and a load bearing axle of the train.

2. The method of accelerating the movement of trains having a primary propulsion unit which consists in providing an auxiliary propulsion unit normally-disconnected from an axle of one of the train carriage trucks, supplying superheated steam from the steam pipe leading to the primary propulsion unit of the train to said auxiliary propulsion unit and utilizing such superheated steam supply for operatively connecting the auxiliary propulsion unit to the axle of the carriage truck;

3. In combination with 1. vehicle havin primary and auxiliary propulsion units an a common motive supply source therefor, controlling devices for the main propulsion unit carried by the vehicle, means operable independently of said controlling devices for establishing connection between the auxiliary propulsion unit and the motive power supply for the primary propulsion unit and additional means for governing the supply of the motive agent to the aux1liary propulsion unit, said means automatically controlling the driving connection between the latter propulsion unit and its load.

4. In combination with a steam locomotive, its control means and an auxiliary pro-- pulsion unit, means connecting the superheated steam supply line for the main engine of the locomotive to said auxiliary proauxiliary propulsion unit upon opening the throttle valve of the locomotive.

5. In combination with a locomotive, its control devices and an auxiliar propulsion unit, a single .throttle contromeans for the auxiliary propulsion unit comprising means for supplying steam from the locomotive boiler to said ropulsion unit, said means includin a fluid pressure actuated valve operated independently of the steam control devices for the locomotive and in-- terposed inthesteam supply line between the supply connections tothe main engine and the auxiliary propulsion unit.

6. In combination with a steam locomotive having a main driving engine, an auxiliary propulsion unit, a single throttle control means for the main engine and the auxiliary propulsion unit comprising a supply connection between the superheated steam supply of the main engine and said auxilpressure. contr steam controlling devices for the ,locomo tiye whereby the main engine and the aux-,

ihary propulsion unit are simultaneously rendered effective or ineffective and the o eration of the auxiliary unit controlled so ely by the steam supply throttle valve of the locomotive. a

7. In combination with a vehicle having a primary propulsion unit, an auxiliary pro-.

ilary propulsion units for steam locomotives, means for entraining the propulsion unit with an axle to be driven thereby, means for supplying steam from the 1000 motive boiler to said propulsion unit, and means interposed in the steam supply l ne and operatively connected to sald entrainment means operable under the pressure influence of the steam to establish a driving connection between the propulsion unit and" said axle prior to the full speed operation of said propulsion unit. 1 v

9. In a controlling mechanism for auxiliary propulsion units for steam locomotives, gearing adapted to entrain the propulsion unit with an axle to be driven thereby to drive the latter in either direction, means for supplyin steam from the locomotive boiler to sai elements of the entrainment gearing and operable independently-of each other to efi'ect the entrainment of the propulsion unit with said axle to drive the latter in the desired direction prior to of saidunit.

.10. In a controlling mechanism for auxiliarypropulsion units for steam locomotives, a. train of gears for transmitting power from the auxiliary propulsion unit to an axleto positively drive the latter, and. means independent of the steam controllingpropulsion unit, and steamol ed devices interposed n the steam supply line, connected to different the full speed operation training said auxiliary motors with the respective wheel axles and elfectively oper- 1 5 ating said motors and the locomotive engine through the medium of a common energlzing agent.

. 12. The method of aiding a locomotive engine in the propulsion of a train which consists in arranging a plurality of auxiliary motors in normally disconnected relation to the wheel axles of different carriages of the train to be driven by the respective'motors and effecting the operation of the locomotive engine and said auxiliary motors through the medium of a common energizing agent and utilizing said agent-for the purpose of establishing an operative connection between said motors and the respec-tive wheel axles simultaneously with thev initial operation of said motors.

13. In combination with a plurality of propulsion units each associated with an axle ,to be driven thereby, controllable means connecting said propulsion unitsin series with a common power supply source, and means automatically actuated by the energizing medium for said propulsion units for simultaneously effecting an operative connection between each of the propulsion units and the associated axle.

14-. In combination with a plurality of propulsion units, each associatedwith an axle to be driven thereby, controllable means connecting said propulsion units in series with a common power supply source, and means automatically actuated by the energizing medium for 'the propulsion units and simultaneously with the initiation of theoperation of each propulsion unit to effect an operative connection between the propulsion unit and the associated axle.

'15. In combination with a primary propulsion unit, a plurality of auxiliary propulsion units, each associated with an axle to be driven thereby but normally disconnected from said axle, an energizing source for the primary propulsion unit, controllable means connecting the auxiliary propulsion units in. series to the source of energy for the primary propulsion unit, and means automatically actuated by the energizing medium simultaneously with the initiation of theoperation-of each of the auxiliary propulsion units to effect an operative connection between each unit and the associated axle whereby said auxiliary propulsion units are effectively operated when the energizing medium is supplied to the primary propulsion unit;

16.. In combination with a locomotive engine, a plurality of auxiliary propulsion units each associated with an axle to be driven thereby but normally disconnected from said axle, a source of energy for the 10- comotive engine, controllable means connecting said auxiliary propulsion units in series with said ener izing source for the locomotive engine and operable to elfect the operation of the auxiliary propulsion units at maximum power output irrespective of vari-' ations in the power output of the locomotive engine, and means automatically actuated by the energizing medium upon the initial operation of each of the propulsion units to eflect an operative connection between the propulsion unit and the associated axle.

unit and the axle.

the axle whereby 18. In a controlling mechanism for auxiliary propulsion units for steam locomotives, normally idle power transmitting gearing for connecting said propulsion unit to. an axle to be driven thereby, and independently controllable fluid pressure responsive devices for operatively connecting said gearing with the latter is driven in the desired direction.

'19. In a controlling mechanism for an auxiliary propulsion unit for steam locomotives, means for supplying steam from the locomotive boiler to said propulsion unit,

.normally idle power transmitting gearing for connecting'said propulsion unit with an axle to be driven thereby, and controllable .fluid pressure responsive means interposed in the steam su ply line to be actuated by the pressure in uence of the steam to operatively connect the gearing withsaid axle and'driv'e the latter intlie desired direction.

20. The method of accelerating the move ment of trains having a primary. propulsion unit which consists in providing an aux1l-, iary propulsion unit normally disconnected from an axle of one of the train carriage trucks thereof, supplying superheated steam from the steam pipe leadin to the power propulsion unit to said auxihar propulsion unit, utilizing such superheate steam supply for operatively connecting the auxiliary propulsion unit to the axle of the carriage truck, and also, in controlling the super heated steamsu ply to the auxiliary propulsion unit in ependently of the steam control devices of the locomotive other than the usual single throttle Valve whereby said propulsion unit may beoperated at maxi' mum power output irrespective of variations 1n the power output of'the primary propulsion unit.-

i In testimony that we claim the foregoing as our invention we have signed our names hereunder. a v

JOHN A. McGREWQ JAMES Ti LOREE. 

